Precision square



Aug. 29, 1950 N. P. SJOBRING PRECISION SQUARE 2 Sheets-Sheet 1 FiledFeb. 25, 1948 Lar c INVEN 0R. M1 252 /%,/37M A... I f QTTOIZNEYJ' Aug.29, 1950 N. P. SJOBRING 2,520,571

PRECISION SQUARE Filed Feb. 25, 1948 2 She ets-Sheet 2 l I I I I I.IIIIIIIIIIIIIIIIIIHI I I I I I I IIIIIIlllIlHIlllIlH JNVENZOR.

OBNEVS Patented Aug. 29, 1950 UNITED STATES PATENT OFFICE PREGISIONSQUARE Nels/P. Sjobring, Los-Angeles, Calif.

ApplicationFebruary 25, 1948, Serial No: 10,694

8 Claims;

The present invention relates to improvements in precision squares.

More particularly, the: present invention relates to squares suchasthose' used by-tool makers and'other artisans; the particularimprovement residing ina construction and arrangement whereby the squaremay be extended: to provide a. precision rule or may be folded;intocompact form.

An object: of the present invention is to provide=w an improved squarehaving-J the features above referred to and having'the advantage thatanywear which may occur'may be. readily'taken unandicompensated' for;

A- further object is toz providera foldable. square whichm'ay be used asa rule, in which looseness of parts will beavoided.

further object is to provide improved meansfor. uniting the two l'egs ofa precision: instrument which may be used as a! square or a rule wherebysaid legswill beaccurate'lymaintained in their desired positions.

A further object: is to provide a precision instrument: having; legswhich may: be accurately: disposed in right angular'relationship-witheach other or whichmaybezextended in astraightline to provide: a rule.or? whichmay be folded: fiatwis -Vagainst' each: other'for storage:purposes;:the instrument: having: the advantage that precision ismaintain-ed" while the: instrument is in' use:

Alfurther object is to provide: an instrument of: thekind just referred:to in which: any wear which may occur through: IOIlg' and constant.usemay' be-readily compensated for;

Further objects will appear as th'e'description' proceeds.

Referringitothe drawings- Eigure: 12 is a. top/plan-a view ofioneembodim'ent:

of the present -invention; the parts being extend-- ed to? prcvideaprecision; rule;

Figure 2 is a top plan viewshowing-the: instrument: with: the blades inright angular-relatiom' ship foruseas a square;

FigureB. is a toppla-nviewshowing: the'instrument in a-collapsed,non-use position, that: is, in a position for storage within aatool boxor the like;

Figured-is a view-in side elevationwof: the instrumentinthepositiontillustrated iniFigure 3:

Figure"- 5-is alvi-ew inside elevation of the instrument in theipositionillustrated in Figure 1;

Figure 6 .iss a: sectional View taken along the plane indicated by thearrows 6'-6 in-Figurev1;

isaview. similar to. Figured but shows a modification Figure 8 is abottom plan view of: a slightly modified construction, theparts beingextended;

Figure 9* isa view on an enlarged scale; partlyin section, thesectional" portion thereof being taken along the plane indicated by thearrows 9'9 of Figure 8 Figure. 10' shows a further modification, partsthereof being illustrated in their relative posi tions'to' provide asquare;

Figure 111 is a View similar to Figure' 10 but showing the parts inextended positions;

Figure 1 2 is a fragmentaryview partly in section taken along theplaneindicated by the arrows l2-I'2 of'Figure 11'; and

Figure 13 is an enlarged: detailed: view of a portion of the weartake-up mechanism.

Referring first. to Figures 1V to 6; the numerals l0 and I I'-indicatetWo'bla-de's, of which the'blade l fl'may'be referred to as thebase-blade, and the blade H- may'b'e referred to as the-foldableblade.

The base blade It! isprevided Withthe parallel, straight sides edges Inaand Nib andwith the parallel, straight endledges I00 and l-Ool,the-edges I00 and: llldbeinglin-precise right-angular relationship withthe edges Illa and lb; The blade H is provided with the parallel,straight sideedges Isl-wand l-l-band-with theparallel, straight endedges: He and d, the edges He and Ltdbeing inprecise right-angularrelationship with theedges Maand H1). Saidblades are graduatedin inchesor other units of length starting with the edges Hid-and Ho and areadapted tobe accurately positioned in end-to end relationshiptovprov-idera rule as-illustratedin-Figure 1. Saidbladesr-are alsoadapted to be disposed in rightangular relationshipwith-each other inthe man-- ner illustrated in Figure: to provide. asquare. Saidbladesareconnected to-each' other through connector mechanism indicatedas a wholeby the numeral I2 Said connector mechanism l2 providesnotonlyfor thearrangements provided for: in Figures-1'and'2but-also for a collapsedarrangement of. the twoblades asillustrated in Figures-3 and' lr Theconnector mechanism I-Z, illustrated in- Fig-ures' 1' to 6 inclusive,includes a the foot 'portion [3* adapted to: be securedto the base bladeHi byineans-of the rivets: lr l' lll or other preferred means.-- Thefoot portion I3- at one of its-extremities is provided with the" hubl5which iscentrally apertured, the: aperture being defined by the:coni'cal'seat It; the approximatelycylindrical-wall ll and theopeningit! of less diameter than the cylindrical wall ll. Said aperture is ad pd 1' 9 receiv a stud I9 which is rivetedor i for the reception of a nut22.

' cylindrical wall 3 I otherwise secured to the foldable blade I I. Said7 stud I9 is provided with the boss 20 of conical conformation adaptedto conform to the conical seat I6. Disp'osedwithin the chamber providedby the cylindrical wall I! is the coil spring 2|.

The upper extremity of the stud I9 is threaded Disposed between the bossI and-the nut 22 is a washer 23. The

side edges Illa and Illb of the blade Ill will be in alignmentrespectively with the side edges Na and Nb of the blade II when theparts are in extended position as illustrated in Figure 1 Moreover, asmentioned above, the end edge I00 and the end edge IIc of the blades II]and II,

respectively, will be disposed in precision rightangular relationshipwith the side edges of the blades Ill and II whereby when said blades Iti and II are in abutting end-to-end relationship,

the necessary alignment between the blades I0 and II will be had.Moreover, when the blade I I is disposed in right-angular relationshipwith the blade ID, the abutting relationship between the end edge II'Icof blade In with the side edge Ila or the side edge III) of the blade IIwill provide an accurate right angular relationship between the bladesI0 and II as the parts are illustrated in Figure 2. To accomplish thisresult the axis of swing of the foldable blade is equidistant from theadjacent end edge He, the side edges Ha and III) of the foldable bladeII, and from the adjacent end edge We of the base blade. In order tomove the blades II! and II relative to each other, it'is necessary onlyto loosen the nut 22 an amount sufficient to allow the blade I I to beswung clear of the blade I0. Under these conditions the blades may bedisposed either in alignment with each other or in right angularrelationship with each other after which the nut I9 will again betightened to provide a rigid relationship between said blades. Moreover,if it is'desired to dispose of the blades in flatwise engagement witheach other as illustrated in Figures 3 and 4, after the nut 22 has beenloosened sufiiciently. thetwo blades may be disposed in the relationshipreferred to afterwhich the nut 22 will be tightened to hold the blade Ifin frictional en agement with the underside of the blade I D. Tofacilitate the positioning of the blade II with respect to the end ed eIIlc of the blade IIJ, said end edge may be slightly beveled asindicated by the numeral 26. r

' Referring now to Figure 7, 'a slightly modified construction ofconnector mechanism is illustrated. Said connector mechanism, which isin dicated .by numeral 21, includes the foot portion 28 adapted to besecured to the base blade I 0 by means of the rivets I4|4 or otherpreferred means. The foot portion 28 at one of its ex- "tremitiesisprovided with the hub 29 which is centrally apertured, the aperturebeing defined by the conical seat 30 and the approximately I Theaperture defined-by the cylindrical wall 3| is adapted to receive thestud 32 which is secured to the blade II by riveting .or other preferredmeans.

' 33 is longer than the bearing boss of the construction illustrated inFigures 1 to 6. The construction illustrated in Figure 7 obviates thenecessity for any coil springs, the co-operating conical portionsco-acting to compensate .fOl'

Wear. 7

Figures 8 and 9 show a connector construction somewhat similar to thatillustrated in Figures 1 to 6 but in a square having a base blade ofrelatively large cross sectional area. The base blade 34 illustrated inFigures 8 and 9 has a dimension parallel with the axis Of swing of thefoldable blade 40 sufliciently wide that said base blade will, whenresting upon a horizontal surface, hold ltheblade in a vertical positionwhen the instrument is being used as a square. The dimension parallelwith the said axis of swing is sufliciently great that no foot portionlike the number I3 or 28 is required. In the embodiment of the inventionillustrated in Figures '7, 8 and 9, as in the embodiment illustrated inFigures 1 to 6 inclusive, the axis of Swing of the foldable blade isequidistant from the adjacent end edge and the side edges of saidfoldable blade and from an end edge of the base blade.

The instrument illustrated in Figures 8 and 9 can be used either as asquare or as a rule or the blades may be folded into, side by siderelationship in the manner discussed above in connection with Figures 1to 6 and Figure 7.

Figures 10 and 13 inclusiveillustrate a further modification of themechanism for connecting the two blades. The base blade 4| on one sidethereof is provided with a channel indicated by the numeral 42 whichchannel communicates with the end 43 of said base blade, the other end.of said channel being rounded as indicated by the numeral 44. The faceof the base blade 4|, on the side thereof which is provided with thechannel 42, is cut away to provide the aligned shoulders 45 -45 disposedtransversely of the blade 4|; Said shoulders 4545 are adapted to beabutted by the end 46 of the foldable' blade 41 or by either, side edge41a or 4') of said blade 41,,and, to accomplish this result, the axis ofswing of the blade 41 is equidistant from the edges and the edges 41aand 41b.

The channel 42 is adapted to receive the movable wear plate "48, saidwear plate being slidable within said channel 42. Sam Wear plate 48 isprovided with the elongated aperture 49 having the side walls 50 and 5|whichtaper toward the base of the channel 42. Said walls. 50 and 5|converge toward the'rounded end 52 of the aperture 49 and diverge towardthe rounded end 53 of said aperture 49. -The base 'blade 4| is providedwith a threaded aperture for receiving an adjusting screw 54 whichadjusting screw has a tapered head adapted to engage the tapering walls50, 5| and 52. Said screw 54 is provided with the screw pressure slot55.) The foldable blade 4? is provided with the stud 55, riveted orotherwise secured to the foldable blade 41. Said stud is provided withthe conical surface 51 adapted to engage the tapering walls 50,

'53 and 5I'of the wear plate 48. Said stud 56 is adapted to be disposedwithin an aperture 57 in the end portion of the base blade 4|. The upperextremity of the aperture 51 is defined by the annular wall 58 and theupper surface of the conical portion 5l of the stud 56 is de fined bythe annular wall 59. Disposed between the walls 58 and 59 is the coilspring 60. The plate '48 and the adjacent portion of the base plate 4|provide a housing for the stud 56 and the spring 60. The upperportion ofthe stud 56 is threaded for the'reception of the nut 6|.

The distance between theaxis of swing of the foldable' blade 41 and eachedge 41a and 41b equal to th ist nce between" said axis of swing amon -1and the end edge 46 of 'said 1 blade and equal-to the: distance-betweensaidaxis of" swingand the shoulders 4545,

' The mode of operation of the constructionof Figures *to- I3will-beolear without detailed explanation. It may bestated; however,that the wear plate Ml, together-with: the dual h'old ing means embodiedin the said screw- 54 and stud" 56, insuresa fixed precisionconnectionbetween" the parts and: permits the t'alteup of any loosenesswhich mightotherwise occur afterprolongeduse; I

In allof the embodiments of? the-invention illustrated and described;manual actuatin ofthe thumb nut permits the loosening of the two bladesrelative; to each other-whereby saidl'bla'd'es may beswung-relative toeach other to provide a precisionsquare or. a precision rule orto penmitthe parts to be disposed in side by side relationship for. storage. The,movable blade is secured in the desi'red'relati'onshi'p with the baseblade-by the applicationof aturning" movement upon the adjusting nut.

Thouglrapreferred embodiment of the present invention has been describedin detail, many modifications will occur to those skilled. in the art.It. is, intended" to cover alliv such modifications that fall within thescope of' the appended claims.

What is claimed is:

l. A foldable precision instrument comprising a base blade, a foldableblade, connector mechanism connecting said blades, said base bladehaving an end edge portion and also having a housing, said foldableblade having parallel side edges and having a stud projectin from saidblade, said stud and said housing having cooperating tapering seats andreleasable means for holding said seats in tight engagement with eachother, said foldable blade being swingable about the axis of said stud,the axis of said stud being equally distant from each of the twoparallel side edges of said foldable blade and from the adjacent endedge of said foldable blade and from an end edge of said base blade.

2. A foldable precision instrument including a base blade, a foldableblade, connector mechanism for swingingly connecting said bladestogether, said base blade having a housing portion, said foldable bladehaving a stud projecting therefrom and disposed within said housingportion, said stud and said housing portion having co-operating taperingseats and releasable means for holding said seats in tight engagementwith each other, said foldable blade having parallel straight sideedges, said base blade havin a straight side edge adapted to be alignedwith one of the side edges of said foldable blade, said base blade andsaid foldable blade having end edge portions disposed in right angularrelationship with said side edges of their respective blades, the axisof said stud being equally distant from the parallel side edges of saidfoldable blade and from said end edge portions of said base blade andsaid foldable blade,

3. A foldable precision instrument including a base blade, a foldableblade, connector mechanism for swingingly connecting said bladestogether, said base blade having a housing portion, said foldable bladehaving a stub projecting therefrom and disposed within said housingportion, said stud and said housing portion having cooperating taperingseats and releasable means for holding said seats in tight engagementwith each. other, said foldable blade having parallel straight sideedges, said base blade having: a straight: side edge adapted tobealigned with: one of the side edgesor said foldable blade, said baseblade; and said foldable blade having end edge portions disposed. inright: angular relation.- ship withsaid side edgesof.theirrespectivevblades, the axis of said stud being equally distant-fromthe=parallelside edges ofisaidfoldable bladel and from said.v endedgeportions of said base blade and said foldable-blade, a, spring:encircling said stud located within said; housing portion, and a nut:threaded-i upon: said stud for; releasably holds ing said seats: intight! engagement with: each other.

41 foldable precisioninstrument includingin combination, abase blade, afoldable blade and connector mechanism for swingingly connecting said":blades together, said connector mechanism including a: stud secured tosaid foldable blade and extending through an end portion off said baseblade, said stud having a conical seat, said conne-ctormechanismalso'including a plate carried within said base blade; said pl-atebeing, pro.- videdwith an elongated slothaving taperingwallsprovidinga--seat, releasablemeans for urging said seats into tightengagement with. each other, a set screw: having a head providing aconical bearing surface adapted to engage the tapering walls of saidslot at one end of said slot, the conical seat of said stud beingadapted to engage the tapering walls of said slot at the other end ofsaid slot.

5. A foldable precision instrument including, in combination, a baseblade, a foldable blade and connector mechanism for swinginglyconnecting said blades together, said connector mechanism including astud secured to said foldable blade and extending through an end portionof said base blade, said stud having a conical seat, said connectormechanism also includin a plate carried within said base blade, saidplate being provided with an elongated slot having tapering Wallsproviding a seat, releasable means for urg ing said seats into tightengagement with each other, a set screw having a head providing aconical bearing surface adapted to engage the tapering walls of saidslot at one end of said slot, the conical seat of said stud beingadapted to engage the tapering walls of said slot at the other end ofsaid slot, said slot being of progressively varying width from end toend.

6. A foldable precision instrument including, in combination, a baseblade, a foldable blade and connector mechanism for swinginglyconnecting said blades together, said connector mechanism including astud secured to said foldable blade and extending through an end portionof said base blade, said end portion providing a housing portion, saidstud having a conical seat, said base blade having a groove at theportion thereof adjacent to said housing portion and being provided withshoulder means disposed in precise right angular relationship with aside edge of said base plate, a plate disposed within said groove, saidplate being provided with an elongated slot having tapering wallsproviding a seat, releasable means for urging said seats into tightengagement with each other, a set screw having a head provided with aconical bearing surface adapted to engage the tapering walls of saidslot at one end of said slot, the conical seat of said stud beingadapted to engage the tapering walls of said slot at the other end ofsaid slot.

7. A foldable precision instrument including, in combination, a baseblade, a foldable blade and connector mechanism for swinginglyconnecting said blades together, said connector mechanism including astud secured to said'foldable blade and extending through an end portionof said base blade, said end portion providing a housing portion, saidstud having a conical seat,

said base blade having a oove at the portion thereof adjacent to saidhousing portion and being provided with shoulder means disposed inprecise right angular relationship with a side edge of said base plate,a plate disposed within said groove, said plate being provided with anelongated slot having tapering walls providing a seat, releasable meansfor urging said seats into tight engagement with each other, a setscrewqhaving aheadvprovided with a conical bearing surface adapted toengage the tapering walls of said slot at one end of said slot, theconical seat of said stud beingadapted to engage the tapering walls ofsaid slot at the other end of said slot, said slot being ofprogressively varying width from end to end.

8. A foldable precision instrument including, in combination, a, baseblade, a foldable blade and connector mechanism for swinginglyconnecting said blades together, said connector mechanism including astud secured to said foldable blade and extending through an endportion, of said base blade, said stud having a conical seat, said V ofsaid base blade.

connector mechanism also including a plate carried within said baseblade, said plate being provided with an elongated slot having taperingwalls providing a seat, releasable means for urging said seats intotight engagement with each other, a set screw having a head providing a'NELS 1 SJOBRING.

REFERENCES orrEn The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 521,597 Altpeter June 19, 1894750,725 Stephens, Jan. 26, 1904

